Work spindle for thread milling machines



Oct. 19, 1937.

R. R. RABER ET AL WORK SPINDLE FOR THREAD MILLING MACHINES Filed June50, 1956 IN VE/V TOPS E A? Parse a-wd F J'LA eso/v BY ATTORNEY PatentedOct. 19, 1937 PATENT OFFICE WORK SPIND'LE F R THREAD lVIILLING MACHINESRobert R. Raber, West Hartford, and Frederick J. Larson, East Hartford,Conn, assignors to 'Niles-Bement-Pond Company,

N. Y., a corporation of New Jersey New York,

Application June 30, 1936, Serial No. 88,182

4 Claims.

This invention relates to thread and other types of milling machineshaving work rotating spindles and particularly to means for applying africtional resistance against rotation of the 5 work supporting androtating spindle during the milling operation and to permit thisfrictional resistance to be adjusted and applied and released as desiredduring the operation of the machine.

A primary object of the invention is to apply brake bands surrounding aportion of the work spindle of a thread milling machine, these bandsbeing supported within the headstock of the machine at their pivotal oradjacent ends and having their opposite ends resiliently forced towardeach other by suitable spring controlled means, the pressure exerted bythe spring means being adjustable over a wide range to apply any desireddrag upon the spindle and to eliminate all 26 lost motion during themilling operation.

Another object of the invention is to provide means operated by acontrolling lever of the machine to engage and separate the ends ofthese brake bands torelease them from engagement with the work spindle.when the operating lever has been moved from its position assumed duringthe normal or cutting operation of the machine.

And finally it is an object of the invention to 30 support the brakebands for slight lateral adjustment within the headstock so that thesebands may fit closely to the spindle and uniformly engage its surfacethroughout its circumference.

With the above and other objects in View our invention includes thefeatures of construction and operation set forth in the followingspecification'and illustrated in the accompanying drawing. 7

In the accompanying drawing annexed here- 40 to and forming a part ofthis specification, we have shown our invention embodied in a form ofthread milling machine having an indexable spindle retained within adriving sleeve, but it will be understood that the invention can be 5otherwise embodied and that the drawing is not to be construed asdefining or limiting the scope of the invention, the claims appended tothis specification being relied upon for that purpose.

In the drawing: V

Figure 1 is a longitudinal sectional, view through the axis of the worksupporting and rotating spindle.

Fig. 2 is a cross sectional view taken upon the plane of the line 22 ofFig. 1. In the above-mentioned drawing We have shown but one embodimentof the invention which is now deemed preferable, but it is to beunderstood that changes and modifications may be made within the scopeof the appended claims withoutdeparting from the spirit of theinvention.

Briefly and in its preferred aspect, our invention may include thefollowing principal parts: First, a headstock within which may belongituclinally supported a work rotating spindle hav-' ing workclamping means atone end; second, a driving sleeve surrounding a portionof the work spindle and adapted for rotation with the spindle indiiierent relative angular or indexed relations thereto; third, adriving gear for rotat ing the sleeve and spindlev preferablykeyeddirectly to the sleeve and having a sleeve-like projection formedthereon; fourth, semi-circular brake bands surrounding the sleeveportion of the driving. gear pivoted to each other at one end andflexibly connected to a portion of the headstock for limited Verticaladjustment; fifth, means connecting'the free ends of the brake bands.having a helical spring at one end and a nut threaded upon the bolt atthe opposite end so that the brake bands may resiliently engage thedriving gear with any desiredpressure; and sixth, a controlling leverpivotally mounted and having an arm with spaced oppositely disposedlugs. thereon, these lugs adapted to enter a gap between the free endsof the brake bands in oscillated position of the lever so that the brakebands are forcibly separated and disengaged from the surface of thedriving gears.

found that better and faster milling together with longer cutter life isobtainable when the work spindle and cutter spindle rotate in oppositedirections. The usual practice, however; has been to rotate the spindlesin the same direction so that the feed of the work was against oropposite the direction of rotation of the cutter. This was necessary asno means were provided for eliminating lost motion or back lash in thework rotating mechanism. To operate the work and cutter spindles to givethe improved results re-' quired the work spindle to be entirely freefrom lost motion to prevent irregular rotation due to the "work spindlebeing subjected to the uneven:

cuttingaction. This pressure varied widely in amount and direction sothat the spindlewould chatter during the milling operation. 'By placinghad to be made, however, so that this resistance 4O 7 V V havingacylindrical surface adapted .to be en-'-.

could'be released/during the setting upof the machine when it wouldbe{necessary to rotate: the spindle by hand] and also it was desirablethat this resistance be released while the spindle a was beingrapidly'rotatedt o 7 1 Referring more" in ,detail 'to the figures of thedrawingiweprovide a'headstock I forming part of a thread*millingmachine-such asishow'nin the patent to Blood 1,588,003 or of any otherstandard type; Rotatablymounted within this headstock'is a spindle'rl I-havingfwork clamping t means I2 at one end, those shown being in "theform of a collet chuck adapted tobe opened andclosed by rotation ofthreaded collar l3 inthe'j usual mannenflSurroundihg the spindle I1 isI, a driving sleeve l llextendinga' portionjof the 'leng thtofthespindle ll and direetly engaging a j bearing surface formed in theheadstock 10'- within which it rotates, ,Thez spindlell and: drivingsleeve [4 are secured togetherYby' in-' dexable' meansfpermittingangular adjustment for milling multiple screw threads. .In operation 7these members are held in'adjusted angular 'rela- 7 'tion toieach otherand rotate simultaneously'to- V Adjacent the opposite endof the spindle"I I 1 there is provideda bearing surface *l6 in the V "tained axiallyin position on' the spindle ll-by aicollar 'l9 threaded onthe end ofthedriving sleeve and engaging against an end of the gear I8. I

tainedlin' fixed position within the headstock I0. 7

I This saddle member engages the spacing member 24 on the pivot orf pin23"for the yoke mem ber "2| ruponjop posite vertical surfaces" soithatvlimited vertical adjustment of the yoke members.

ZLisTpermitted while still being retained against rotation.

gether while the milling of a thread is taking place' headstock l0throughwhich the spindle passes,- tliere being an adjustablecollar l1outside the it headstoc'k l0 threaded upon the spindle H and a retainingthe spindle against axial movement 'Torotate-the spindle II and itsdriving sleeve' I4; there is keyed to the sleevea gear I8. As

shown in Fig.1 thiss gear l8 engages against a 1 shoulder formed-on thedriving sleeve and is re- Formed on the gear I8 is a sleeve'portion 2V0gaged'by the surfaces of yoke membersZ l. Pref erabl athei yoke members2| are substantially semi-circular and. are lined with suitable material 22 such as moulded brake lining of asbestos or other materialtoprovide-substantial frictional v engagement with the sleeve portion 20of the gear l8. *Attheir upper ends the yoketmembers' V 2lvaretpivotedto each other by means of a pint 23, there being a spacing member 24also mountred' on the pin 23 and disposed between the piva.

oted ends of the yoke members 2 I To retain the yoke members 2| againstrotatio-n'with the spindle Hand driving sleeve l4 the spacing member 24is slidable within a saddle member '25 re- The opposite o'r lower endsof the yoke mem- V ber 2| are extended a short distance jbelow thespindle H and are resiliently drawn toward each other intofrictionalengagement with the sur face ofthe sleeve portion ZilbyaspringZi upon a bolt 2'! mounted as shown inmFig- 2. A'threadj2lagainst the surface ofthe sleeve'portion 20.;

ed nutf28t on'the end of the bolt 21 opposite the end on which thespring 26 ismounted permits 7 adjustment ofthe pressure of the yokemembers a lever 30 is pivotally mounted onshaft -M. this shaft 3| are'mounted twoarms 35' preferably "As above described the engagement oftheyoke members 2| frlctionally against the: surface 2 0 is requiredonly :during'the cutting operation and- ,this' engagement should bereleased duringthe 7 setting up of the machine andduringrapidtraversing'movementof the; cutter, s V As. indicated in 'Fig; 2', afstarting: ofcontrol formed upon a single member} keyed to the shaft andhaving their free'endsdisposed in opposed relation-to eachother andpositioned between the lower ends of the yo-ke m embers 2I;;In either'oscillated position otthe arms 351mm. their cen-' tral position showninFig. 1 the endjof onearm will 'be forced between the ends of the yokemembersr2l. 'Heads 3fi'may be-provided' on the mem} A bers 2| andsuitably secure dltheretoin position to engage thearms 35. 7 Whenforcedbetween 7 the contacting members or" heads 36 either arm 35,Wi11force the yoke members 2| apart and out of contact with the surface'20so that the spin dle ll may be rotated without friction.

What we claim is:

- 7 1. In a thread milling machine'in combination,

a headstock, a spindle rotatably supported there face. 7

gage a surface on said spindle, and' a lever move from said spindle; r Yr 3; In a thread milling machine in combination; Y r aheadfstock, aspindlerotatablysupportedthere in,'work clamping'means thereon, adriving gear on said spindle intermediate the ends thereof, yoke memberssupported within said headstock and-i adapted normally" to resilientlyengage a surface on said spindle, and means; to: disengage said membersfromengagement with saidjsur in, work clamping means thereon, adrivinggear V on said spindle intermediate the ends" thereof,

yoke members pivotally supported, withincs'aid r'" headstock andadaptedto surround and' engage a' surface on said spindle, a springresiliently forcing saidyoke members intoengagement with said surface,and means interposed between the V free 'ends of said yoke members todisengage said 7 members from said "surface;

7 4. In a thread milling machine in combination,

a headstock; aspindle rotatably'supported there- 5 V in; workclamping'means thereoma driving gear on said spindle intermediate theends thereof;

yoke memberssupported withingsaid headstock I 2 and surrounding saidspindle, a pivotal connec- 6 tion between adjacent ends of saidi yokemem-- bers,'means to support said pivotal connection= within saidheadstockforfree movement toward 7 '7 and from said spindle, aspringlresili'ently forcing said yoke members intoenga'gement withsaidspindle, and means interposable between the free ends of saidyoke'membersttqdisengage said members from the spindle. V

t Romu- RQRABERH:

FREDERICK J. LARSON.

